Craquelure

Craquelure is when a picture or painting has many small lines on it, like a spider web. Imagine if you drew a picture with a crayon and then crumpled it up into a ball and then smoothed it out again - you might see some little lines or cracks in the paper. That's kind of what craquelure looks like on a painting. It happens when the paint on the painting gets old and starts to dry out and shrink a little bit, which makes those little lines appear. It can make a painting look more interesting and valuable, but it's also a sign that the painting might need some extra care to keep it from getting damaged.